I recently took a job as a small engine mechanic and am in charge of the weeders, chainsaws, and all other 2-cycle powerplants. One day before clocking out I got on the computer to check the cost of a Poulan 46. I wanted to see if a Shortblock (complete engine without carburetor, igniton, muffler). From what I can see it is not available that way, but the components to build it are all available. You can buy a cylinder assembly(with piston), crank assembly(with rod and bearings), a wrist pin bearing. This should be all you need to start building an engine, minus ignition of coarse. The cost for all the above mentioned parts are about $100.00 retail.

Now let's say you bought a CH Ignition conversion kit for this engine which retails for $208.00.

We are up to $308.00.

But we forgot the muffler and carburetor. I think another $100.00 will buy both, which brings us up to $408.00.

Is that too much for a brand new engine?

For those that want to say you will "still have a conversion" need to look around, because most engines we fly have a far different background. Most are originally from saws and such. Yes DA, 3W, and the such are not from that arena, but were not talking about that much money either. The average DA-50R set-up will cost you $600.00 without stand-offs, unless you buy somebody's used engine. Used engine.

If you go out and buy everything the way you are suggesting, a conversion is no deal. I built a 45 CC homelite conversion with a CH ignition. I also have a DA-50 and a ZDZ-80. The conversion is a nice project and I had fun with it, but it is not in the same league as the DA-50 or the ZDZ-80. A conversion works because you get a good deal on the core engine, or because it gives you satisfaction to build it, or because you want to connect the world of general purpose 2-cycle engines to the world of model aircraft engines. In my case it was all three. If you're trying to make a killing in the engine market, you are in for a disappointment, I beleive. Conversions also require tinkering. The muffler I bought from a well-known vendor uses thread-in pipes. These quickly vibrated out, despite my using engineering cement to hold them in. I had to go get them aluminum welded, and I am still nervous about them. Additionally, conversions often have lower standards than the top engines do. For example, my Homelite has a single stud mounting the prop. My DA-50 has a threaded crankshaft plus four cap screws. The DA-50 is ported to run at low RPMs and high torque. The Homelite is not. The one place you can do well is to buy the engine cheaply, and then keep the conversion cost low, by leaving the magneto in place, etc. Cheaper airplane engines like Zenoah are set up this way, and our conversions do tend to resemble them more. I went the "whole route" because I wanted to see what I could do on my own, and I wanted to understand the relationship between a chainsaw engine and a model airplane engine at a higher level than most of the guys at the field do. BTW, one of the better pilots where I fly is a mechanic in a shop like yours. He keeps talking about building a conversion, but he flies a DA-100. I like my conversion and I am glad I did it, but I have no illusions about it. Finally, if you like the idea, get busy and build one. Then tell us about it!

well thats if you buy the engine new i got one homey for free from my future father in law who has an electric now. the other homey i got on ebay for 22 bucks. i dont plan on getting a CH ignition but rather sticking with the magneto's that came on them. the mount and prop hub i make with my dad's help(because he has access to the tools since he is a tool maker). now i might get on ebay and get a walbro carb or two that has a bigger opening for 15 to 20 dollars. now at the most for one engine i have 40 dollars spent when the zenoah is 299 or 399 i forget. it has the magneto as well. i will still have a reliable engine however spent alot less. i have a used cap 232 i bought for 125 bucks that is the right size for the homelite. i wont get unlimited verticle but i am not a good enough pilot to take advantage of that anyhow. secondly i learn alot about how small 2 cycle engines work. its all based on the individual choice i feel i have more to gain by converting in the long run than buying a 400 dollar engine.

While I will agree doing conversions are fun, I will disagree on the statements that have been made here regarding cost and viability of conversions -VS- "airplane" engines. CH Ignitions cost at least $50.00 less than stated. Bought 6 of them now for my conversions. Why buy all the parts for a Poulan? You can buy the whole saw for less than that at times brand new, sell the leftovers. Heck I got 30 bucks for the bar and chain! Paid $70 dollars for the whole saw from sears. Poulan makes Craftsman. Sure the Poulan 42 may be a tad heavier than my true BME 50 but in my sons Sig Extra 300 it has unlimited verticle. Total cost breakdown: Saw $70, hub and sensor bracket $39.00, muffler $28.00 all welded, CH Ignition $145 with Bosch cap. Grand total of $282.00. Less than half of the cost of a so called airplane engine. Remember that BME singles are right out of the Echo chainsaw line. Have a BME 50 in my Wildhare Extra 300LX. Had to invest $650 or so in it. Just started 2 new projects based on the Echo short blocks. CS4400 = BME 44 and a CS510 = BME 50. Paid $350 for both short blocks. Hubs, mufflers, and ignitions will cost me another $250 or so to buy, but I am making everything but the ignitions. Carbs are all over RCU and Ebay for way less than one may think. Get some G10 board for the carb spacer, a 2" by 2' bar will make blocks for at least 20 engines. Paid 22 bucks for mine. By the way BME uses a single prop shaft. Never had an issue with mine. Just my experience.

Add to this the fact that you can always move the CH ignition from plane to plane! It's nice to have each plane all flight ready, but not necessary. For the cost of the sensor, ($7.50 I think), the engine can be flight ready and all you do is plug in the ignition unit.

I would NEVER cough up $400.00 or more for a gas engine. 90% of my conversion engines I got for free or a few bucks. Make all the parts yourself, buy the ignition, and have a blast. Thats what I do. (You don't even have to buy the ignition but I always do to save some weight and make for easier starting.)

AV8TOR

Don't forget the bragging rights about how you made a model airplane engine from a chainsaw or whacker?

Enjoy,

Jim

And that truly is priceless. People can hardly believe it!!

AV8TOR

New Echo 58cc short block; everything but the carb and exhaust for our applications, $200.00 more or less. Carb out of the junk box, homemade exhaust and prop hub, ignition off one of my other engines. Still just a whole lot cheaper than $400 to $600 bucks!

Yep, conversions are cool!

AV8TOR

Guys I'm really torn.

I have a 45cc Echo blower, runs perfect.
I am thinking seriously about converting it.

There ia a guy selling 50cc Homelites converted for RC inclides everything.... $250.00

There ia a guy selling 46cc Pouland converted for RC inclides everything.... $240.00

Both have flywheels and apear to have been done right, especially the Homelite.

Should I convert, or should I buy a conversion. And which conversion should I get?

Will the Echo be the best of the bunch?

What do you think?????

Hi av8tor,
Do you have the part number for that 58cc shortblock or saw model number? I have 44cc and would like to build a larger Kioritz engine.

Thanks Dave

Add to my original post that the Echos are very powerful. That is whay Keith at BME does them. I have also converted a 23.6cc from a blower. Flying my Balsa USA Eindecker very scale and turns a cheap Master Airscrew 18/6 at better than 7500 RPM all day with ease. Got 3 string trimmers from a landscaper for free for more projects. By the way Dave, I will let you know when I get them apart if you are still interested in the "left overs".

Still interested, thanks Tim

Echo 58cc "Short Block" (complete engine without accessories) #SB1020

http://www.smallenginepartswarehouse.com/parts.asp

On the "What to do" question, if you don't need the blower, I would convert it. You will have the satisfaction of doing it yourself, and use the money you would have spent on the other motors for airplanes or accessories! I think the power levels would be fairly close, with the Echo having a possible edge.

AV8TOR

for me the conversions vs. ready-made topic is pretty close to kit/scratch vs. ARF debate. the ARF will many times come out cheaper especially if you consider you time worth something but you simply won't get the same satisfaction out of it! depends what you want out of the hobby.

even though i get most of my engines for free the end result would be expensive if i tallied up all the time and running around i do to get them converted. sure i could just buy a ready made hub and mount but that would take alll the fun out of it...for me anyways


dave

Where are you guys getting the G10 board from?

http://www.mcmaster.com/

http://www.jjorly.com/g10_fr4_sheets_fabricator.htm

or maybe ook up G10 on Google?

Enjoy,

Jim

I had looked on Google and only found sheets that were way too big and way to expensive. The McMaster site has a piece 5/8" thick by 4"x6" for $9.36. That looks like what I will get. Is 5/8" a good thickness to get?

[link=http://www.jjorly.com/g10_fr4_sheets_fabricator.htm]http://www.jjorly.com/g10_fr4_sheets_fabricator.htm[/link] has a competitive price, they just sell in 3ft x 4ft sheets...
Plus I called the company (JJ Orly) today and they said that they also custom cut parts and special sizes out of G10 for the RC community.

When I looked on Mcmaster Carr, I couldn't find a 4" x 6" piece anywhere...and I use Mcmaster all the time. The only size they had that was close to 4 x 6 was 6 x 6 x .625 and it was $31.25, almost 3 times the cost per square foot of the 3' x 4' sheets mentioned above. I also buy G10 board quite frequently would question the true integrity of the material at $9.00 per 4x6" block.

What catalog page on Mcmaster was it on?

How come a person can't completely delete his own post ? Looks kinda dumb with just a period in a big otherwise empty box..

G10 from MSC Industrial supply is $106 for 4 square feet, 3/8 thick...
www.mscdirect.com
$38 for one square foot, $66 for 2 square feet....
The 3/8 thickness is perfect for carb blocks..I have used it for many years...It can be machined just like aluminum, but is more abrasive and is very hard on common high speed steel end mills and drills..I use cobalt drill bits and carbide end mills for longer life....It's best cut with a Makita 4 inch disc grinder, it eats bandsaw blades....

RCIGN1:

What RPMs are you running to mill the G10, I use a 45,000 CNC router...

Some guys have all the toys...
I have an old Webb manual mill...2720 rpm with a 4 flute 1/2" solid carbide end mill.....
Definitely not high tech, just like my ignition systems
And me

I bought it for cheap on EBAY. I use TiCN Coated carbide tools for milling, flood it with soapy water...extends the life of the tools. For cutting blocks, I use a boron coated blade because the G10 FR4 is so abrasive.

I contacted the company above [link=http://www.jjorly.com]www.jjorly.com[/link] and they mentioned that sell smaller pieces and packages of 25 random sizes for carb block applications, probably from over runs of machined parts.

I do a lot of custom work for RC Hot Rods, some planes / helicopters. As far as actually even driving an RC, I rarely get into the "fun" side. I'm more into the design, concept and customization of the mechanical structures of the vehicle and have a lot of friends who are born enthusiasts with RC racing. I'm also a stand in crew chief for races to help people get their cars back in the race if the damage isn't too extensive. I really enjoy it.

It is on catalog page 3350 and Part Number 6842K11